The present invention relates generally to printing presses and more particularly to a spray device on a printing press for spraying a surface of the press.
Spray devices have been used in conjunction with offset printing machines, especially web offset printing machines, to apply liquid to a cylinder surface. A plurality of spray devices are typically mounted on a spray bar, which holds the spray devices at a distance from a surface of the cylinder. Spray devices are used to dampen the plate cylinder with water or a fountain solution as part of the printing process. Typically, the spray devices spray the liquid directly onto a surface of a dampening cylinder. A train of two more dampening cylinders is then used to spread the liquid into a continuous film and to transport the liquid to the plate cylinder. The liquid adheres to the hydrophilic areas on the surface of the plate cylinder to resist the deposition of ink on those areas. Spray devices may also be used for other applications on the printing press, for example, to clean and/or cool other surfaces of the printing press.
U.S. Pat. No. 4,738,400 discloses an elongated spray bar for cooling rollers in a metal rolling machine. The spray bar assembly includes a plurality of nozzles mounted in a bottom plate of the spray bar and independent fluid passageways are defined in the intermediate and top plates of the spray bar.
U.S. Pat. No. 4,708,058 discloses a water pulse spray dampening system for a printing press. The dampening system includes a plurality of spray nozzles disposed on a spray bar. Solenoid valves associated with each nozzle are cycled to open and close the flow of liquid through the nozzles, for example, at a rate of 350 pulses per minute at a full press speed, with the fluid pressure being maintained at 40 psig.
U.S. Pat. No. 5,540,390 discloses a spray bar assembly for a printing press having at least one nozzle and means for selectively opening and closing flow of a liquid through the nozzle. A pair of opposed side walls housing the nozzle help to control the spray of liquid.
U.S. Pat. No. 5,463,951 discloses a printing machine spray device for moistening surfaces of a printing press. The spray device enables small amounts of water to be distributed uniformly over a large surface by moving sprayers of the device relative to the surface as they are spraying.